Methods for testing the fouling tendency of FCC slurries

• US 5,753,802 A
• Filed: 01/14/1997
• Issued: 05/19/1998
• Est. Priority Date: 03/16/1995
• Status: Expired due to Fees

• Current Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Falkler, Thomas J.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Politzer, Jay L.
• Application Number:
  US08/783,158
• Time in Patent Office: 490 Days
• Field of Search: 73/61.62, 73/86, 208/48 AA
• US Class Current: 73/61.62
• CPC Class Codes: C10G 11/187 Controlling or regulating
• CPC Class Codes: C10G 75/00 Inhibiting corrosion or fouling in apparatus for treatment or conversion of hydrocarbon oils, in general C10G7/10, C10G9/16 take precedence
• CPC Class Codes: G01N 17/008 Monitoring fouling
• CPC Class Codes: G01N 33/2805 investigating the resistance to heat or oxidation to the weather, to corrosion, or to light G01N17/00

Abstract

A method for analyzing the fouling tendency of a bottoms slurry in a fluidized catalytic cracking unit, the method comprising the following steps:

(a) subjecting a sample of the bottoms slurry to a selected increased pressure above atmospheric pressure and to a selected temperature corresponding to a bottoms slurry temperature at which the bottoms slurry is proposed to be maintained in the fluidized catalytic cracking unit;

(b) maintaining the sample at the selected increased pressure and selected temperature for at least about two hours;

(c) cooling the sample and reducing the pressure;

(d) homogenizing the sample to produce a homogenized sample;

(e) extracting relatively higher molecular weight materials from the homogenized sampling and

(f) analyzing the extracted relatively higher molecular weight materials for at least one equality

wherein the steps (e) and (f) are carried out by:

(g) adding from about three to about five parts by weight of a solvent composition to one part by weight of a measured amount of the homogenized sample, thereby to form a liquid phase containing relatively low molecular weight slurry components and a precipitate phase containing relatively high molecular weight slurry material as a precipitate;

(h) separating out the precipitate; and

(i) analyzing the precipitate for at least one quality.

Claims

1. A method for analyzing the fouling tendency of a bottoms slurry in a fluidized catalytic cracking unit wherein the bottoms slurry is maintained approximately at a bottoms slurry temperature, the method comprising the following steps:

(a) subjecting a sample of the bottoms slurry to a selected increased pressure above atmospheric pressure and adjusting the temperature of the sample as necessary for the sample to reach a selected temperature approximately equal to the bottoms slurry temperature;

(b) maintaining the sample at the selected increased pressure and selected temperature for at least about two hours;

(c) cooling the sample and reducing the pressure;

(d) homogenizing the sample to produce a homogenized sample;

(e) evaluating non-deposited aggregation formed within the sample, by;

(i) extracting relatively higher molecular weight materials from the homogenized sampling and

(ii) analyzing the extracted relatively higher molecular weight materials for at least one quality from which the fouling tendency of the bottoms slurry can be determined.

2. A method as set forth in claim 1 wherein the step (e) (i) is carried out by:

adding from about three to about five parts by weight of a solvent composition to one part by weight of a measured amount of the homogenized sample, thereby to form a liquid phase containing relatively low molecular weight slurry components and a precipitate phase containing relatively high molecular weight slurry material as a precipitate and separating out the precipitate; and

wherein step (e)(ii) is carried out by;

analyzing the precipitate for at least one quality.

3. A method as set forth in claim 1 wherein the sample is maintained in step (b) at the selected increased pressure and selected temperature for at least about three hours.

4. A method as set forth in claim 1 wherein the fluidized catalytic cracking unit includes a bottom with a pump-around which recycles the bottoms slurry from a point in the bottoms, through the pump-around and back to the point in the bottoms in a residence time and the sample is maintained in step (b) at the selected increased pressure and selected temperature for a period of time corresponding to at least about twice the residence time.

5. A method as set forth in claim 3 wherein the homogenization of step (d) is carried out by agitation of the sample.

6. A method as set forth in claim 2 wherein the solvent composition comprises about 94 to about 96 parts by weight heptane per five parts by weight pentane.

7. A method as set forth in claim 6 wherein the solvent composition consists essentially of about 94 to about 96 parts by weight heptane per five parts by weight pentane.

8. A method as set forth in claim 6 wherein the solvent composition is nonaqueous.

9. A method as set forth in claim 2 wherein the liquid phase is formed by adding about four to about five parts by weight of the solvent composition to one part by weight of the measured amount of the homogenized sample.

10. A method as set forth in claim 6 wherein the liquid phase is formed by adding about four to about five parts by weight of the solvent composition to one part by weight of the measured amount of the homogenized sample.

11. A method as set forth in claim 7 wherein the liquid phase is formed by adding about four to about five parts by weight of the solvent composition to one part by weight of the measured amount of the homogenized sample.

12. A method as set forth in claim 2 wherein the precipitate is separated out by pouring off the liquid phase and then heating the precipitate to evaporate off solvent in the precipitate.

13. A method as set forth in claim 2 wherein the quality for which the precipitate is analyzed is weight.

14. A method as set forth in claim 2 wherein the quality for which the precipitate is analyzed is mass.

15. A method as set forth in claim 2, further comprising, prior to step (a), the step of obtaining the sample of the bottoms slurry by withdrawal of the sample of the bottoms slurry from the fluidized catalytic cracking unit.

16. A method as set forth in claim 1 wherein the sample is held in a non-metallic container during at least steps (a) and (b).

17. A method as set forth in claim 2 wherein the fluidized catalytic cracking unit includes a bottom with a pump-around which recycles the bottoms slurry from a point in the bottoms, through the pump-around and back to the point in the bottoms in a residence time and the sample is maintained in step (b) at the selected increased pressure and selected temperature for a period of time corresponding to at least about twice the residence time.

18. A method as set forth in claim 17 wherein the solvent composition comprises about 94 to about 96 parts by weight heptane per five parts by weight pentane.

19. A method as set forth in claim 18 wherein the solvent composition consists essentially of about 94 to about 96 parts by weight heptane per five parts by weight pentane.

20. A method as set forth in claim 18 wherein the solvent composition is nonaqueous.

21. A method as set forth in claim 18 wherein the liquid phase is formed by adding about four to about five parts by weight of the solvent composition to one part by weight of the measured amount of the homogenized sample.

22. A method as set forth in claim 21 wherein the quality for which the precipitate is analyzed is weight.

analyzing the precipitate for at least one quality.

23. A method as set forth in claim 1, further comprising the step of determining the fouling tendency of the bottoms slurry from the at least one quality.